Currently, smoked cocaine or "crack" is thought to have greater addictive effects than other routes of cocaine administration, including intravenous administration. Surprisingly, despite the fact that smoked cocaine represents one of the most serious medical and social challenges to our society today there are no data from humans on the levels of cocaine that actually reach the arterial blood stream enroute to the brain. The purpose of this study is to directly compare the effects of smoked cocaine to those of intravenously administered cocaine primarily on the kinetics of cocaine in both arterial and venous blood. Standard cardiovascular measures and subjective effects will be evaluated concurrently with the arterial and venous blood draws. Subjects will have current histories of using cocaine by both routes of administration. Subjects will be exposed to 3 doses of smoked cocaine or "crack" and 3 doses of intravenous cocaine. To date we have obtained the IND to administer smoked cocaine. We have also met several times with the anesthesiologists to review the protocol and technical details with the study nurses. We are planning to recruit our first subject mid-May.